aggravation

I have a supercharger installed and there is an adjustable fuel pressure regulator installed. According to the receipts from the previous owner who did the install it is from 928 Specialists Prod ID 928.110.198.04 Fuel - Pressure Reg. - Adjust. - 88-95

Will this be ok to leave in and use the SharkTuner to tune my car. It seems to be working fine right now but I only have the seat of the pants, an Innovate Motorsports wide band O2 sensor with A/F gauge and an occasional plug check to verify that.
Other components are the "H" test pipe, rear muffler bypass, no cats, small resonators, and a set of chips (no specs on the chips).

I'm hoping to buy the SharkTuner soon and trying to anticipate any other expenses that I will have to deal with to get the most out of it.

Vilhuer

John will surely give best possible advice soon but I would change back to stock regulator. There is no need for higher pressure if injectors are large enough. There are only down sides left in using adjustable.

stuartph

I was thinking of using an AFPR with 42LBS and a ST but i'm not sure if i have the correct pressure regulator, i think its the same as the one aggravation has.

Cheburator

have you fitted the Leda's yet? how are you finding them on the brilliant roads that we have in the SE of England?

stuartph

Alex


Noooooooooo have them still in the box, just been to busy, i've got so much to do on the GT, i dont think it will be on the road this year.

BrianG

Yes, you have the same adjustable FPR that I have, and with the Shark Tuner you will be able to find the best fuel pressure for your system as you tune. I have 30# injectors and have found that a FPR setting of 48-50 psi is best (no vacuum) for my setup. (this is, incidentally, the pressure of the OEM '85-86 FPR)

aggravation

Escellent! I also have the 30# injectors. So you literally don't connect the vacuum line to your regulator?

John Speake

Hi Aggravation
I would leave a vacuum feed to the adjustable FPR you have. Se t the pressure to what Brian says. At that pressure the injector spray patterns will be good. The SharkTuner will allow you to set up the mappong with a good range of adjustment.

You can also change the "injector size" parameter in the ST program up and down in value to compensate for youyr base setting.

I can send you a copy of the User Manual if you send me an email to the link on my website. That will asnwer most of your potential questions.

If you are interested in a ST let me know in sufficent time as final assembly is done to order, so allow a couple of weeks.

aggravation

Thanks, I already have a copy of the manual, one read and following a few posts from Louie Ott and some others convinced me I needed to buy one!

I tried to call 928 Specialists this morning to order one but they must be closed.
If the cost is the same I'll be happy to order it from you but I figured the shipping would be cheaper from them since they are a few hundred miles from me and you are a few thousand.

As far as starting the assembly, please start at your earliest convenience, I managed to put aside the funds for it so I'm 100% committed to buying it now!

Any chance on creating a breakout box device for the chips to reside in with a second set of sockets to plug in the SharkTuner with an A/B switch to switch between the two sets of sockets?
I envision the two ribbon cables permanently attached to the breakout box mounted on the shelf under the glove box, being able to plug my laptop into the SharkTuner (also on the shelf) which is already attached to the breakout box, flip the switch and fire up the car and run in software mode to monitor things, create new map files etc. then switch back to chip mode, disconnect the laptop, go inside and burn some new chips if necessary etc. etc.

Just thinking outside the box

John Speake

OK ! It should be possible to entend the EPROM sockets on ribbon cables, although their length should be kept as short as possible. I think switches would be an unecessary complication and expense, as it would be simpler to unlpug the chip, and then plug in the SharkTuner/laptop. A quick release socket would make this quick and easy.

As long as the implemenation was good, it should be reliable.

aggravation

I may be trying to be too clever by half here...
I've never removed the chips or accessed the two computer boxes. If repeatedly pulling and re-inserting the chips/plugs isn't any big deal then perhaps there is no need for the external access points.
I only thought of it because every other time I touch something plastic or rubber on this car it crumbles and turns a 30 minute job into 3 days down time waiting on the FedEx truck to bring me my parts!

daveo90s4

John, Aggravation,

I reckon being able to extend the eprom sockets on a short ribbon cable would be great and would make subsequent ST runs much easier to do. But how to neatly run the ribbon cable with eprom socket out of the standard 928 chip 'box' when it is all assembled with tabs bent over etc?. John, one option possibly would be to offer this as an option, with the option including a new cover with nicely machined slit, with the ribbon passed through the slit and then the sockets attached, and additional costs. Of course this assumes that these covers are available. Maybe on an exchange basis for those who order this option?

But wouldn't the WB O2 sensor still need to be installed / uninstalled each ST session (since it needs to be powered when engine is running, and that is done through the ST?). To make things even easier is there any way that the WB O2 sensor can be kep in, and powered, permanently?

Dave
90 S4
Dubai
Rennlist Member (ex User)

aggravation

In my case I have two O2 sensors. I have the narrow band sensor that feeds the cars computer just as always. Then I welded a second bung into the "H" section of my exhaust pipe and installed a wide band O2 sensor there. It is powered from a fuse that is hot upon turning the key to the on position. That sensor feeds its signal to an Innovate Motorsports LC-1 and their XD-16 air fuel gauge.

So I can plug the output of the wide band sensor into the SharkTuner pretty easily I suspect by way of the cabling provided by the Innovate Motorsports gear....

Louie928

You may be over complicating here. The cables attached to the LH/EZ-K need to be short and minimum amount used. The LH/EZ-K is susceptable to RFI when the cover is off and external stuff is connected. Once you have chips made for your installation, you are pretty much done. There should be no need for periodic tweaking. Agreed, it may take several tuning periods to get the mixture and timing as you want it. You can leave the LH/EZ-K out on the floor during that time and swap chips if you don't want to fire up the ST and laptop to run the engine. You can make two different maps for different fuels or conditions and switch between the maps (on the same chip) by switching the coding plug configuration.

John Speake

[QUOTE=daveo90s4]John, Aggravation,

I reckon being able to extend the eprom sockets on a short ribbon cable would be great and would make subsequent ST runs much easier to do. But how to neatly run the ribbon cable with eprom socket out of the standard 928 chip 'box' when it is all assembled with tabs bent over etc?. John, one option possibly would be to offer this as an option, with the option including a new cover with nicely machined slit, with the ribbon passed through the slit and then the sockets attached, and additional costs. Of course this assumes that these covers are available. Maybe on an exchange basis for those who order this option?
>>>>>>>>>>>>>>
Hi Dave,
Louie's observations are correct, and this type of arrangement would have to be carefully engineered, with special lids etc. so as not to cause issues.

As this would be a rather special "one off" it would be up to the experimenter to modify lids etc. It would not be economic for me to do this.

I am prepared to offer guidance....
>>>>>>>>>>>>>>>>>>>

But wouldn't the WB O2 sensor still need to be installed / uninstalled each ST session (since it needs to be powered when engine is running, and that is done through the ST?). To make things even easier is there any way that the WB O2 sensor can be kep in, and powered, permanently?
>>>>>>>>>>>>>>>>>>>>>
It is possible to keep an WBO2 system in place on a permanent basis, as these units usually provide a simulated narrow band output which can the looped back into the standard O2 sensor plug.

The WBO2 is not switched or powered by the SharkTuner, it is wired into the car.